(a) Field of the Invention
This invention relates to novel compounds classified in the field of organic chemistry as 3-aryl-3-heteroarylphthalides and 3,3-bis(hereroaryl)phthalides useful as color precursors, particularly in the art of carbonless duplicating as, for example, in pressure-sensitive systems, in thermal marking systems and in hectographic or spirit-reproducing copying systems; to substituted 2-(indolylcarbonyl)benzoic acids and 2-(pyrrolylcarbonyl)benzoic acids useful as intermediates to the subject phthalide color precursors; to processes for preparing said phthalides and benzoic acids; and to pressure-sensitive duplicating systems, thermal marking systems and hectographic copying systems containing the same.